Question

Rationalise the denominator :-​

Answer 1

Answer:

$\frac{1}{7 + \sqrt{40} } \times \frac{7 - \sqrt{40} }{7 - \sqrt{40} } \\ = \frac{7 - \sqrt{40} }{ {7}^{2} - \sqrt{40 ^{2} } } \\ = \frac{7 - \sqrt{40} }{49 - 40} \\ = \frac{7 - \sqrt{40} }{9}$